1. Field of the Invention
The present invention relates to a roll sheet holder which rotatably holds a roll sheet wound on a cylindrical sheet core and is removably mounted in a tape printer provided with a feeding device for feeding the roll sheet and a printing unit for printing on the roll sheet. Further, the present invention relates to a tape printer in which the roll sheet holder is removably mounted.
2. Description of Related Art
Heretofore, various types of tape printers have been proposed to print characters and others on a long sheet formed of a self-adhesive sheet applied with a release sheet by means of a thermal head. Some tape printers of this type are provided with a roll sheet wound on a sheet core, a roll sheet holder which rotatably holds therein the sheet core, a support mechanism which removably mounts the roll sheet holder in the tape printer, and a feeding device for feeding part of the roll sheet while drawing the roll sheet from the roll sheet holder. The roll sheet holder may be selected from among plural holders of different sizes individually corresponding to plural sheet widths.
For instance, one of such roll sheet holders is disclosed in Japanese patent unexamined publication No. 2001-270660. This roll sheet holder, which is used in a tape printer provided with a feeding device for feeding part of a roll sheet wound on a sheet core, detachably holds the roll sheet wound on the sheet core and is rotatably mounted in the tape printer. Specifically, the roll sheet holder comprises a first support shaft which is inserted in a cylindrical through hole of the sheet core at one end thereof, a second support shaft which is inserted in the through hole of the sheet core at the other end thereof and is removably engaged with an end face of the support shaft, and a guide member which is slidably fitted on the outer periphery of the first support shaft and held in contact with the end face of the roll sheet. The first support shaft has a first flange formed on the periphery of the outer end face of the first support shaft, one or more slide grooves formed in the periphery of the first support shaft in the axial direction thereof, and a plurality of guide grooves formed extending from each slide groove in a peripheral direction and spaced apart at predetermined intervals in the axial direction of the first support shaft. The second support shaft has a second flange which is formed on the periphery of the outer end face of the second support shaft and held in contact with the end face of the roll sheet. The guide member has one or more locking piece(s) which formed protruding radially inwardly from a sliding surface of the guide member and is fitted in the slide groove or guide groove. When the locking piece is engaged in the corresponding guide groove, the roll sheet is allowed to be held between the second flange of the second support shaft and the guide member.
The above roll sheet holder can provide the following advantages. In the case where the roll sheet holder is demounted from the tape printer to replace the roll sheet with another one of a different width and then is mounted again in the tape printer, the roll sheet can easily and surely be set in the holder. It is also possible to prevent the loss of parts of the roll sheet holder, thus preventing failures caused due to the loss of parts. Consequently, product reliability can be enhanced.
However, the conventional tape printer which mounts the above mentioned roll sheet holder has the following disadvantages. To rotatably support the roll sheet holder, it is necessary to mount additional two unit holders on the right and left sides respectively and then fit the mounting piece protruding outside each unit holder in a pair of unit support members vertically provided on the inside bottom of the tape printer. The tape printer has to be provided with the pair of unit holders in addition to the guide member fitted on the outer periphery of the first support shaft. This would result in an increase in number of parts and a complicated structure, leading to a troublesome mounting work of the roll sheet holder. The pair of unit support members and others need be provided on the inside bottom of the tape printer, which makes it difficult to achieve a reduction in size of the tape printer.